Ripping is used in mines, quarries and similar industrial establishments to break up bodies of rock and ore. In the past, ripping has been accomplished by use of a tractor or bulldozer pulling a ripping tool behind it. Heavy, powerful tractors, commonly called bulldozers, are provided with hydraulically controlled mounting means on the rear end. A plow or ripping shank is movably mounted upon this mounting means and can be raised and lowered hydraulically by the operator of the bulldozer. Ripping is accomplished by lowering the ripping shank into the ground behind the bulldozer and moving the bulldozer in a forward direction. The ripping shank or plow is drawn through the ground fracturing the rock before it so that it may be removed and further processed.
In the past, rippers have consisted of a fixed shank extending downwardly from the rear of the bulldozer and a replaceable tip on the shank. The ripping action was achieved entirely by the force generated by the forward movement of the bulldozer transmitted through the ripping shank to the ripping tip.
While ripping was useful in many applications, it had its problems. The only force acting on the ripper was the force of forward motion of the tractor. Hard or tightly laminated rock was very difficult to rip or could not be ripped at all. Ripping of some rocks was uneconomical. Ripping of some rocks required close operator attention and high levels of operator skill as the operator had to match control of the tractor and ripper to variations in rock strength and lamination thickness. Ripping operations were also hard on the tractor and ripper. As all the force used in ripping was generated by the tractor moving forward, wear on the entire tractor has accelerated.
In addition to the above described problems, ripping of many types of rock were simply too difficult and expensive to be economically feasible.
Attempts have been made to overcome these problems by use of impact hammers acting on the ripping shank. U.S. Pat. No. 4,679,857 describes a mounting frame for bringing an impact hammer on a heavy tractor. However, problems prevented the economical use of such arrangements. One major problem was impact hammer tool life. The portion of the impact hammer which strikes the ripping shank is a heavy steel cylinder which is often hardened called the tool. The tool must be easily replaceable as it is short lived compared to other elements of the system. However, the tool must have a reasonable service life or ripping cannot be economically achieved. In prior art impact hammers used in ripping the tool failed too often. The tool would fail by spalling, cracking, or otherwise. Ripping tractor down time for tool replacement and the like and the cost of tool replacement and the like prevented widespread use of impact hammer ripping.
These and other problems are overcome by the present invention wherein an hydraulic impact hammer is successfully mated to a ripping shank drawn by a heavy tractor.